Etifoxine is chemically named as [6-chloro-2-(ethylamino)-4-methyl-4-phenyl-4H-3,1-benzoxazine]. A hydrochloride salt of etifoxine, Stresam, is sold in France for the treatment of anxiety. Etifoxine was originally disclosed in U.S. Pat. No. 3,725,404. Although etifoxine is chiral, as far as the inventors are aware, there is no disclosure of its resolution or asymmetric synthesis. Etifoxine has a depressive effect on the central nervous system and is an anticonvulsant. It is also known to have tranquilizing effects, narcosis-prolonging effects and analgesic properties. See, e.g., Corisco et al., Psychopharmacologia (Berl.) 45, 301-303, 1976.
Etifoxine hydrochloride has been extensively studied and reportedly can be used in the treatment of a variety of disorders. For example, European Patent No. EP1273301, German Patent No. DE3439055 and U.S. Pat. Nos. 3,725,404 and 6,638,528 disclose uses of etifoxine as an anticonvulsant, a tranquilizer and an anxiolytic drug. It has been reported to act as a modulator of GABA receptor complex activity. See, Hamon et al., 2003, Neuropharmacology, 45, 293-303.
There remains a need for methods of using the same for treating anxiety and other conditions.